LIMA, Peru — Peru has reversed seven years of continuous growth in its coca crop with U.S. assistance but has nevertheless unseated Colombia as the No. 1 global producer of the plant that is the basis for cocaine, the United Nations announced Tuesday.

Peru cut its area under coca cultivation by 3.4 percent last year to 241 square miles (62,500 hectares) from 2011, according to the U.N. Office of Drugs and Crime.

Last month, the U.N. announced that Colombia’s crop was down 25 percent to 185 square miles (48,000 hectares). But it held off until now with word that Peru had regained a distinction it had not held since the mid-1990s.

Peru counterdrug agency chief Carmen Masias said Colombia had the advantage of more than $6 billion in U.S. aid beginning in 2000 in trimming its coca crop. And unlike Colombia, Peru’s eradication of drug crops is manual. In Colombia, U.S. contractors spray herbicide.

But while U.S. aid to Colombia decreases, it is on the rise in Peru.

More than $55 million in U.S. counterdrug assistance that includes airlift and alternative development helped Peru eradicate 54 square miles (14,000 hectares) of coca last year, and that amount was doubled to $100 million this year, half of Washington’s total assistance to Peru, officials said.

Unlike Colombia, most cocaine produced in Peru is exported not to The United States but to Brazil, Argentina and Europe. Much of it is smuggled by air and land through Bolivia, the world’s No. 3 coca-producing country with a crop about a third the size of Peru’s.

Drug policy experts caution that a greater area under cultivation does not necessarily mean more cocaine production. Higher-yielding coca hybrids and improved refining techniques, at which Colombians are especially adept, are also factors.

President Ollanta Humala made battling illicit narcotics a priority when he took office in 2011. He embraced expanded U.S. counterdrug assistance and also dedicated Peruvian funds to eradication for the first time — $11 million in 2012. Masias said Peru would likely double that next year.

Humala has in addition had success against Shining Path rebel remnants that protected drug traffickers in the Upper Huallaga Valley, the cradle of Peru’s cocaine trade. It captured a top rebel there last year and is prosecuting a former congresswoman from the region for alleged drug trafficking.

The U.N. says Peru reduced the Upper Huallaga coca crop by 23 percent last year. However, coca plantations have sprung up in a new region — the Amazon jungle state of Loreto bordering Brazil and Colombia, where the U.N. said the crop was up 73 percent from 2011.

The region with the most coca in Peru — the Valley of the Ene and Apurimac rivers known as the VRAE— has some 20 percent of the crop and a strong rebel presence.

Masias has said no region of Peru is off-limits from coca eradication. But she has not said when the government might begin eradication in the VRAE.

Rebels have killed nearly 100 troops there since 2008. Last month, troops killed to two top Shining Path commanders in the region.